The present invention is directed to methods for merging data streams. More specifically, the invention is directed to methods for merging data streams from base stations in a cellular mobile radio telephone network.
In cellular mobile radio telephone services, full coverage is usually achieved by spatially arranging base stations such that the areas covered by the cells associated therewith overlap. When a subscriber moves from within one cell to within another cell, the call is forwarded to the second cell's base station by handing over the call at the cell boundary.
In reality, the cell boundaries are not sharply defined but have a more or less diffuse character which depends on topographical conditions. In order to reliably forward the subscriber to a neighboring station and to avoid multiple handovers, the cells are designed to overlap. However, this leads to higher infrastructure costs and, thus, to reduced economic feasibility of mobile radio telephone networks.
What will be referred to herein as soft handovers, also called macro diversity, has been proposed for future networks in order to avoid this disadvantage. In this arrangement, the connection to a mobile station is maintained by two or more base stations when the mobile station is located in a cell boundary region. The signals of the participating base stations are then routed to a common point. A quality criterion, for example the average reception field strength during the reception of a voice block, is associated block by block with a signal. That block of the various blocks which are forwarded to the unification point which has the best quality criterion, is the block selected for being propagated to the next network element.